This is a revision of a proposal to continue studies on the synthesis and biological evaluation of new radiopharmaceuticals for detecting and quantifying normal and neoplastic tissue growth and metabolism. Three major areas will be explored. 1) Agents which localize in collagen. A number of disorders are associated with collagen changes. In addition, neoplastic tissues must lyse or otherwise penetrate collagen barriers. An approach to localization in collagen is based on inhibition of the collagen crosslinking enzyme lysyl oxidase. Radioactive syntheses of a lysyl oxidase irreversible inhibitor, beta-aminopropionitrile (BAPN) are suggested. As soon as BAPN can be made rapidly and quantitatively, the compound can be produced with C-11. Several analogues of the compound which can be labeled with gamma-ray emitting radionuclides, are suggested. Binding to the carbonyl groups generated by lysyl oxidase is also proposed, and production of a number of suitable gamma ray/positron emitting compounds is discussed. Syntheses for radiolabeled proline analogues are given, as an additional procedure for collagen localization. 2) A new approach to synthesizing a wide variety of labeled pharmaceuticals is proposed by means of arsenic radionuclides. Arsenic can substitute for P, N+ or even C, in various organic molecules. Because of this, and the fact that As has several radionuclides (including As-71) with desirable imaging characteristics, syntheses are outlined for a variety of physiologically important compounds, such as arsenoacetylcholine, arsenoalcohols, arsenolipids and others. 3) Approaches are described for "biochemical mapping" or tracing out the location and quantity of body constituents by means of radiopharmaceuticals. Use of enzyme substrates or inhibitors will be the initial area of study. These 3 topics hold promise of providing noninvasive tools for evaluating normal and neoplastic tissue growth and metabolism during life.